It is known to provide a motor vehicle having stop/start functionality in which an engine of the vehicle is switched off to save fuel when conditions permit such as when the vehicle is held stationary with a driver-operated brake pedal depressed. The condition in which the vehicle is held stationary with the engine automatically switched off during a drivecycle is known as an ‘eco-stop’ condition.
When the driver releases the brake pedal the engine may be restarted and a transmission of the vehicle may be re-engaged. That is, under ‘no fault’ normal operating conditions, release of the brake pedal by the driver triggers the engine to be restarted, the driveline to be closed and torque to be transmitted to the drive wheels.
It is also known to provide a hybrid electric vehicle (HEV) having an engine and an electric motor. In a parallel-type HEV the engine may be used to provide motive power to the vehicle. The engine and electric motor may be maintained in a stopped condition when the vehicle is held stationary by the brake pedal (i.e. in the eco-stop condition) in order to reduce fuel consumption.
If the vehicle is operating in a parallel mode in which the engine provides drive torque to the wheels, when the driver releases the brake pedal the vehicle may be arranged to restart the engine and re-engage the transmission. Alternatively, if the vehicle is operating in electric vehicle (EV) mode in which the electric motor is used to drive the vehicle and not the engine, if the vehicle is in the eco-stop condition (in which the electric motor is switched off when the vehicle is stationary) the vehicle may be arranged automatically to restart the electric machine when the brake pedal is released.
It is against this background that the present invention has been conceived. Embodiments of the invention may provide a vehicle or a method which improves upon known systems. Other aims and advantages of the invention will become apparent from the following description, claims and drawings.